Yuk Chun Chan, University of Washington, Department of Atmospheric Sciences, Seattle, United States, Christopher D Holmes, Florida State University, Earth, Ocean and Atmospheric Science, Tallahassee, FL, United States, Tomás Sherwen, Wolfson Atmospheric Chemistry Laboratories,, Department of Chemistry, University of York, York, United Kingdom; National Centre for Atmospheric Science, University of York, York, United Kingdom, Xuan Wang, Harvard University, Cambridge, MA, United States, Shuting Zhai, University of Washington Seattle Campus, Department of Atmospheric Sciences, Seattle, WA, United States and Becky Alexander, University of Washington, Department of Atmospheric Sciences, Seattle, WA, United States